Neewbie focal length question

[Brett Blaisdell]

I have a 75 watt epilog and have finally gotten it somewhat dialed in. I am graphic designer and have been doing mostly skateboards. I have a 2" lens now, but will a 4" lens allow me to be able to get the same detail on the tip and tail that I get in the middle of the deck? I am trying to avoid doing multiple passes and hoping a 4" lens is the ticket.
Thanks in advance.

Brett

[Chuck Stone]

The longer lens gives you more depth of focus, but less detail.
If you're looking to hold the detail, then I think your best bet
might be to do the two passes with the 2" lens.
The 2" lens might have a depth of field of 2mm or so, the 4" would
have maybe 6-7mm. More, but not enough to do both ends of the
deck in one pass. Plus, you increase the spot size of the beam, so
your resolution is lower.

[Walt Langhans]

Are you doing the bottom of the board or the top, or both? One thing you might want to consider is something thin that you could engrave / cut and then laminate to the board, that way you wouldn't have to deal with the curves on the ends and you could get creative by using more than one layer and different materials for different looks. Laser cutting designs into grip tape before it goes on to the deck would bad a$$. Sounds like a cool project!

[Brett Blaisdell]

That is why I started my company, was laser cut intricate grip tape for skateboards. I am lasering up the bottoms with all the detail, and minimal on top. Sounds like i am stuck with 2 passes. If you get a sec, check out smuglabs on facebook and let me know what you think. Thanks walt and chuck for your feedback.

[Walt Langhans]

The zombie yetti and the design that you did for your nephew are very cool! 2 passes isn't a bad thing just up your price accordingly for the extra time and effort

[Dan Hintz]

I would suggest trying the 4" lens... unless you're doing ultra-fine detail, you may not notice any difference. If you're engraving into wood, it's a pretty safe bet you won't notice the difference.

[Brett Blaisdell]

Thanks walt. As far the the 4" lens, do I get that directly from epilog or are there other companies I can get it cheaper? Or is this one of those thing where oem is best?

Thanks again for the help.

[Dan Hintz]

Unless you're mechanically inclined and have a lens holder without a lens, I would suggest getting it from Epilog.

[Jeff Greer]

I just bought a 4.0 lens assembly from Epilog and it was $350.00 and it is very nice. I love your work, very jealous of the talent in creating everything!

[Mike Lysov]

I have tried Chinese 4" lens for cutting. I could not find any good point I using them.
However I have not tried them with thick MDF, only with 6mm where 2" lens is more than enough to get almost perfect straight cut with a 100W laser. Speed of cutting for 6mm with 4" lens needs to be at least 30% less than with 2" lens. Bought this lens on ebay so were not expensive to try.

[Richard Rumancik]

Unfortunately no one can really tell you that a 4" lens will work (even though some have) because quality is in the eye of the beholder. What may meet someone else's standards might not meet yours or your customer's. It also depends on the nature of the graphic. So all I can suggest is that you try to do a test on someone else's machine before you spend the $350. Maybe you have an old board you can test on; you just need to make a small graphic at the lowest and highest positions and compare. (Or laminate some veneer to an old board for test purposes.)

When you do the current board you are you focusing exactly on the surface when making multiple passes? If the difference is not too large you can focus at an "average" surface (half way between min and max.) This will average the focus error and make it less obvious. Maybe a 3" lens and this technique combined would work. I know that experiments can be expensive but often there is no other way.

[George M. Perzel]

Brett;
4 inch lens will work fine as long as you are not trying to laser 6 pt or less text-then some fuzziness may occur. Is front, middle and back of board at the same elevation (focus distance)? If you are trying to compensate for different focuses at points on the board, you will have problems or do a lot of trial and error.
Best Regards,
George
Laserarts

[Brett Blaisdell]

Thanks for all your suggestions! All I do is experiment on the daily trying to find better ways to do something. I didn't know they even had a 3" lens...that could maybe be the ticket because I am focusing halfway and getting semi decent results. I just hate the thought of having to to do multiple passes it drives me nuts..guess its my ocd kickin in!

[Richard Rumancik]

Brett, I really don't know what options Epilog has for your machine - but I never considered that to be a limiting factor. Some people have bought loose lenses from Laser Research or eBay and fitted them into holders. I don't know how the lens mounts in the holder on your machine. Maybe you can buy an "empty" holder from Epilog or eBay or wherever (it could even have a broken lens) and replace the lens with what you want.


I think Epilog might just have 2.5 and 4 but you need to check.

[Jim Dawson]

We run a ton of fine detail stuff with the 4". I am also looking into a 7" setup as we speak